One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,11)(8,10)(9,12)(13,14)(15,21)(16,19)(17,26)(18,28)(20,25)(22,23)(24,27) involution — undirected(1,2)(3,4)(7,12)(9,11)(13,15,23,17,19,24,18,25)(14,20,28,27,16,26,22,21)(5,7,8,12)(6,9,10,11)(13,16,19,14)(15,20,24,26)(17,27,25,21)(18,28,23,22)(2,4)(6,10)(9,11)(14,16)(15,24)(17,25)(22,28) involution — undirected(13,17,18,15,19,25,23,24)(14,21,22,26,16,27,28,20)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.